J. Org. Chem. 1984,49,209-210 port of this research and to the National Science Foundation for its contribution to the purchase of a Bruker 360-MHz NMR spectrometer. Registry No. 4,66267-06-9;5, 60968-15-2;benzenebutanoic acid, 1821-12-1; benzenepropanoic acid, 501-52-0; 2naphthalenebutanoicacid, 782-28-5; 2-naphthalenepropanoicacid, 21658-35-5; 1-naphthalenebutanoicacid, 781-74-8;a-methyl-lnaphthalenebutanoic acid, 7498-80-8;3-phenanthrenebutanoic acid, 13728-56-8; 2-phenanthrenebutanoic acid, 77520-30-0; 8,9,10,11-tetrahydro-8-benz[a]anthraceneaceticacid, 6299-45-2; l-pyrenebutanoic acid, 3443-45-6; l-tetralone, 529-34-0; 1indanone, 83-33-0;2,3-dihydro-4(1H)-phenanthrenone,778-48-3; 2,3-dihydro-lH-benzinden-l-one, 6342-87-6; 3,4-dihydro-l(OH)-phenanthrenone, 573-22-8; 3,4-dihydr0-2-methyl-l(2H)phenanthrenone, 3580-60-7;lO,ll-dihydrobenz[a]anthracen-8(9H)-one,5472-20-8;2a,3,4,5-tetrahydrobenz~]aceanthrylen-l(2H)-one, 87883-45-2; 9,10-dihydrobenzo[a]pyren-7(8H)-one, 3331-46-2; benzenebutanoyl chloride, 18496-54-3; benzenepropanoyl chloride, 645-45-4; 2-naphthalenebutanoylchloride, 87883-46-3; 2-naphthalenepropanoyl chloride, 27673-99-0; 1naphthalenebutanoyl chloride, 87883-47-4; a-methyl-lnaphthalenebutanoyl chloride, 87883-48-5; 3-phenanthrenebutanoyl chloride, 87883-49-6;2-phenanthrenebutanoyl chloride, 87883-50-9; 8,9,10,11-tetrahydro-8-benz[a]anthraceneacetyl chloride, 87901-08-4; l-pyrenebutanoyl chloride, 63549-37-1; trifluoromethanesulfonic acid, 1493-13-6.
Reaction of n -,sec-, and tert-Butyllithium with Dimethoxyethane (DME): A Correction John J. Fitt and Heinz W. Gschwend*
Research Department, Pharmaceuticals Division,
CIBA-GEIGY Corporation, Summit, New Jersey 07901 Received November 9, 1983
Two recent communications report on kinetic and spectral evidence for the formation of a complex between metalating agent and substrate prior to deprotonation.'t2 The second account2 describes results obtained in the attempted metalation of formamidines with t-BuLi in dimethoxyethane (DME). The lack of D incorporation in these experiments was rationalized on the basis of a rather stable complex between substrate, metalating agent, and the bidentate solvent (DME). Furthermore, upon addition of benzaldehyde, benzyl alcohol and benzyl benzoate were isolated, the products of an apparent Cannizzarro reaction. We have evidence that the interpretation of these results2 with DME is incorrect. Dimethoxyethane has only rarely been used as a solvent in metalation reactions. Our own previous negative experience with this solvent and the peculiar results of the recent report2 called for a more careful investigation of the stability of DME toward alkyllithiums. In several experiments we have shown that DME has a very limited stability toward butyllithium. With t-BuLi in particular, DME is readily deprotonated and undergoes @-elimination characteristic of several 1,2-diheterosubstituted ethanes. Thus, in contrast to the behavior of tetramethylethylenediamine (TMEDA), DME does not form a stable complex with t-BuLi. As illustrated in Scheme I, it is assumed that after coordination with one of the two oxygen (1)Al-Aseer, M.; Beak, P.; Hay, D.; Kempf, D. J.; Mills, S.; Smith, S.
G. J. Am. Chem. SOC. 1983,105, 2080. (2) Meyers, A. I.; Rieker, W. F.; Fuentes, L. M. J. Am. Chem. SOC. 1983, 105, 2082.
209
-20 "C DME/n-BuLia
-70 "C
111 i. 5
DME/sec-BuLi -2i 1 120 * 5 DME/ t-BuLiC
